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Subject[PATCH v4 2/2] usb: dwc3: core: Support the dwc3 host suspend/resume
Date
For some mobile devices with strict power management, we also want to suspend
the host when the slave is detached for power saving. Thus we add the host
suspend/resume functions to support this requirement.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
Changes since v3:
- No updates.

Changes since v2:
- Remove pm_children_suspended() and other unused macros.

Changes since v1:
- Add pm_runtime.h head file to avoid kbuild error.
---
drivers/usb/dwc3/Kconfig | 7 +++++++
drivers/usb/dwc3/core.c | 26 +++++++++++++++++++++++++-
drivers/usb/dwc3/core.h | 15 +++++++++++++++
drivers/usb/dwc3/host.c | 37 +++++++++++++++++++++++++++++++++++++
4 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index a45b4f1..47bb2f3 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -47,6 +47,13 @@ config USB_DWC3_DUAL_ROLE

endchoice

+config USB_DWC3_HOST_SUSPEND
+ bool "Choose if the DWC3 host (xhci) can be suspend/resume"
+ depends on USB_DWC3_HOST=y || USB_DWC3_DUAL_ROLE=y
+ help
+ We can suspend the host when the slave is detached for power saving,
+ and resume the host when one slave is attached.
+
comment "Platform Glue Driver Support"

config USB_DWC3_OMAP
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 9a4a5e4..7ad4bc3 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1091,6 +1091,7 @@ static int dwc3_probe(struct platform_device *pdev)
pm_runtime_use_autosuspend(dev);
pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY);
pm_runtime_enable(dev);
+ pm_suspend_ignore_children(dev, true);
ret = pm_runtime_get_sync(dev);
if (ret < 0)
goto err1;
@@ -1215,15 +1216,27 @@ static int dwc3_remove(struct platform_device *pdev)
static int dwc3_suspend_common(struct dwc3 *dwc)
{
unsigned long flags;
+ int ret;

switch (dwc->dr_mode) {
case USB_DR_MODE_PERIPHERAL:
+ spin_lock_irqsave(&dwc->lock, flags);
+ dwc3_gadget_suspend(dwc);
+ spin_unlock_irqrestore(&dwc->lock, flags);
+ break;
case USB_DR_MODE_OTG:
+ ret = dwc3_host_suspend(dwc);
+ if (ret)
+ return ret;
+
spin_lock_irqsave(&dwc->lock, flags);
dwc3_gadget_suspend(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);
break;
case USB_DR_MODE_HOST:
+ ret = dwc3_host_suspend(dwc);
+ if (ret)
+ return ret;
default:
/* do nothing */
break;
@@ -1245,12 +1258,23 @@ static int dwc3_resume_common(struct dwc3 *dwc)

switch (dwc->dr_mode) {
case USB_DR_MODE_PERIPHERAL:
+ spin_lock_irqsave(&dwc->lock, flags);
+ dwc3_gadget_resume(dwc);
+ spin_unlock_irqrestore(&dwc->lock, flags);
+ break;
case USB_DR_MODE_OTG:
+ ret = dwc3_host_resume(dwc);
+ if (ret)
+ return ret;
+
spin_lock_irqsave(&dwc->lock, flags);
dwc3_gadget_resume(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);
- /* FALLTHROUGH */
+ break;
case USB_DR_MODE_HOST:
+ ret = dwc3_host_resume(dwc);
+ if (ret)
+ return ret;
default:
/* do nothing */
break;
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index b585a30..db41908 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1226,4 +1226,19 @@ static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
{ }
#endif

+#if IS_ENABLED(CONFIG_USB_DWC3_HOST_SUSPEND)
+int dwc3_host_suspend(struct dwc3 *dwc);
+int dwc3_host_resume(struct dwc3 *dwc);
+#else
+static inline int dwc3_host_suspend(struct dwc3 *dwc)
+{
+ return 0;
+}
+
+static inline int dwc3_host_resume(struct dwc3 *dwc)
+{
+ return 0;
+}
+#endif
+
#endif /* __DRIVERS_USB_DWC3_CORE_H */
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index ed82464..8e5309d6 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -16,6 +16,7 @@
*/

#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>

#include "core.h"

@@ -130,3 +131,39 @@ void dwc3_host_exit(struct dwc3 *dwc)
dev_name(&dwc->xhci->dev));
platform_device_unregister(dwc->xhci);
}
+
+#ifdef CONFIG_USB_DWC3_HOST_SUSPEND
+int dwc3_host_suspend(struct dwc3 *dwc)
+{
+ struct device *xhci = &dwc->xhci->dev;
+ int ret;
+
+ /*
+ * Note: if we get the -EBUSY, which means the xHCI children devices are
+ * not in suspend state yet, the glue layer need to wait for a while and
+ * try to suspend xHCI device again.
+ */
+ ret = pm_runtime_put_sync(xhci);
+ if (ret) {
+ dev_err(xhci, "failed to suspend xHCI device\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+int dwc3_host_resume(struct dwc3 *dwc)
+{
+ struct device *xhci = &dwc->xhci->dev;
+ int ret;
+
+ /* Resume the xHCI device synchronously. */
+ ret = pm_runtime_get_sync(xhci);
+ if (ret) {
+ dev_err(xhci, "failed to resume xHCI device\n");
+ return ret;
+ }
+
+ return 0;
+}
+#endif
--
1.7.9.5
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